Abstract Aim To assess the prevalence and determinants of failure to thrive (FTT) among patients with vesico‐ureteral reflux (VUR) and evaluating the effects of supplementation on growth in patients with urinary solute losses. Methods We retrospectively enrolled 1277 patients with VUR (mean age at diagnosis = 6.5 months). Patients with FTT were screened for renal tubular function impairment (TFI). If fractional excretion of sodium (FENa) &gt;2% or blood bicarbonate &lt;20 mmol/L, supplementation was provided. Results Among 1277 patients, 56 (4.4%) had FTT. Of these, 42 (75%) presented extrarenal causes of FTT, 3 (5.4%) had chronic kidney disease (CKD), 9 (16.1%) had TFI, and 2 (3.5%) had CKD and TFI. FTT occurred in 8/208 patients (3.8%) with and in 48/1069 patients (4.5%) without ( p = 0.68) recurrent urinary tract infections (UTIs). At multiple logistic regression, birthweight &lt;10th percentile, preterm birth, TFI, identified or suspected syndromes and other diseases were predictors of FTT. Eleven (19.6%) patients with FTT had TFI; five with increased FENa and/or acidosis received supplementation and showed catch‐up growth. The remaining six patients exhibited spontaneous catch‐up growth. Conclusion FTT was found in &lt;5% of children with VUR. It was not determined by recurrent UTIs and was mainly associated with extrarenal causes. Supplementation with sodium and bicarbonates could be useful in selected cases.

Prevalence and determinants of failure to thrive in children with vesico‐ureteral reflux